Additive for FCC process

Abstract

The invention includes an additive for maximizing production of olefins. The additive comprises a ZSM-5 molecular sieve, at least one inorganic oxide, and phosphorus oxide. The ZSM-5 molecular sieve has iron in the framework, and the additive comprises at least 0.5 weight percent iron, as measured as iron oxide, in the molecular sieve framework. The additive is useful for maximizing production of olefins in a FCC process.

We claim: 
     
       1. An additive for maximizing production of olefins in a fluid catalytic cracking process, which comprises a ZSM-5 molecular sieve, at least one inorganic oxide, and phosphorus oxide, wherein the ZSM-5 molecular sieve has iron in the framework and the additive has a molar ratio of phosphorus to the combined amount of framework iron and framework aluminum (P:(Fe+Al)) in the range of 1 to 1.3, and the additive comprises at least 0.5 weight percent iron, as measured as iron oxide Fe 2 O 3 , in the molecular sieve framework. 
     
     
       2. The additive of  claim 1  wherein the additive comprises at least five percent by weight phosphorus (as P 2 O 5 ). 
     
     
       3. The additive of  claim 1  wherein the ZSM-5 molecular sieve comprises from about 1 to 5 weight percent iron oxide Fe 2 O 3 . 
     
     
       4. The additive of  claim 1  wherein the inorganic oxide is selected from the group consisting of silica, alumina, silica-alumina, titanium oxide, zirconium oxide, aluminum phosphate, and combinations thereof. 
     
     
       5. The additive of  claim 1  further comprising a clay. 
     
     
       6. The additive of  claim 1  wherein the ZSM-5 molecular sieve comprises 25 to 80 weight percent of the additive. 
     
     
       7. The additive of  claim 1  wherein the ZSM-5 molecular sieve comprises 40 to 70 weight percent of the additive. 
     
     
       8. An additive for maximizing production of olefins in a fluid catalytic cracking process, which comprises a ZSM-5 molecular sieve, at least one inorganic oxide, and phosphorus oxide, wherein the ZSM-5 molecular sieve has iron in the framework and the ZSM-5 molecular sieve has a molar ratio of framework iron to framework aluminum within the range of 0.4 to 0.67, and the additive comprises at least 0.5 weight percent iron, as measured as iron oxide Fe 2 O 3 , in the molecular sieve framework. 
     
     
       9. The additive of  claim 8  wherein the additive comprises at least five percent by weight phosphorus (as P 2 O 5 ). 
     
     
       10. The additive of  claim 8  wherein the ZSM-5 molecular sieve comprises from about 1 to 5 weight percent iron oxide Fe 2 O 3 . 
     
     
       11. The additive of  claim 8  wherein the inorganic oxide is selected from the group consisting of silica, alumina, silica-alumina, titanium oxide, zirconium oxide, aluminum phosphate, and combinations thereof. 
     
     
       12. The additive of  claim 8  further comprising a clay. 
     
     
       13. The additive of  claim 8  wherein the ZSM-5 molecular sieve comprises 25 to 80 weight percent of the additive. 
     
     
       14. The additive of  claim 8  wherein the ZSM-5 molecular sieve comprises 40 to 70 weight percent of the additive.